The output from a load cell is really tiny. Any kind of small interference can crop up and then will be expanded by the signal conditioner. The longer the cable is, the greater the interference will be, because of the amplified coupling. It can be enhanced, if it is screened and twisted pair cable is always used along with a high-quality signal conditioner to eliminate a lot of noise. A particular amount of physical noise is deemed normal, particularly in the load cells which are sensitive in nature. This can come up from a number of sources coming from the computer fans placed on the same desks as the load cell to the fork lift trucks which are driving around on the floor above. The more sensitive your equipment is, the higher the degree of separation needed from the rest of the world. Here are the ways to find faults in the load cells.
- Between the excitation +/- and signal +/-, check the load cell resistance.
Also check the calibration cert that must be the resistance between the excitation +/- and between the signal +/- as well. Determine those resistances with the help of a multimeter in order to verify that there is no kind of internal damage caused to the sensor. Never forget to disconnect the load cell from the signal conditioner before you perform this.
- Inspect the accurate wiring corrections and the color coding
Always check the connections between the signal conditioner and load cells. The color codes tend to vary between the manufacturer and it is always the best idea to assume nothing. Generally, the color coding is always present on the calibration certificate of the load cells. Make sure the wiring is correct or you may get wrong, inverted or biased results.
- Inspect if the load cell is overloaded
A tiny load cell can be rendered overloaded just by leaning on it. If this is the case, then you may have deformed the load cell permanently and it may not reform itself in its original position accurately. This may show up as a non-zero reading in no load. And there are the highest odds that this will be the terminal. Consult your load cell manufacturer for more information. As aforementioned that the voltage outputs resulting from the load cells are quite minimal and can be influenced easily by the external environment. There are a number of ways to minimize the disruption.
